1. Field of the Invention
The present invention relates to a speaker and more particularly, to an evenly elastically deformable damper for speaker, which keeps in balance when vibrated with the voice coil, preventing damage of the lead wires.
2. Description of the Related Art
Speaker, or loudspeaker is an electromechanical device that converts an electrical signal into sound. The term loudspeaker is used for both individual devices (and for complete systems) consisting of one or more drivers in an enclosure, often with a crossover circuit. Technically, speaker is a well developed product. Under severe market competition, diversified speakers are available in the market to attract consumers. Sound quality is an important factor that must be taken into account in speaker design In a speaker, cone paper, damper, voice coil and bonding glue may affect sound quality.
A regular damper for speaker is an elastic fabric member made of cotton, linen cambric or nylon. In a spaker, the damper is provided between the speaker body and the voice coil. Further, the signal terminals at the speaker body are electrically connected to the voice coil through lead wires so that an external electrical signal can be applied to the voice coil through the signal terminals. The lead wires extend over the damper. During operation of the speaker, the sound waves thus produced cause a resonant action of the lead wires. This resonance problem may cause the lead wires to break, or the lead wires may be broken easily during dismounting of the speaker. If the lead wires are broken, an external electrical signal cannot be applied to the voice coil.
To avoid the aforesaid problem, the lead wires may be directly stitched to the surface of the damper, as shown in FIGS. 6˜8. As illustrated, the damper A is a plain weave fabric of elastic warp wires A1 and weft wires A2 shaped like a corrugated disk. During installation, each lead wire B is alternatively extending over the top and bottom surfaces of the damper A, and then the voice coil C is fastened to the center through hole A3 of the damper A and tightly secured thereto, and then the lead wires B are soldered to the respective copper foils (not shown) at the voice coil C. When an electrical signal is applied from a signal source (for example, DVD player) through an amplifier (which amplified the voltage) to the voice coil C, a magnetic field is created by the electric current in the voice coil C which thus becomes an electromagnet. The voice coil C and the driver's magnetic system D interact, generating a mechanical force which causes the voice coil C and the cone (not shown) to move back and forth and so reproduce sound under the control of the applied electrical signal coming from the amplifier. During operation of the voice coil C, the damper A is moved back and forth with the voice coil C. Because the damper A is a plain weave fabric of elastic warp wires A1 and weft wires A2, the elastic deformation of the damper A in X direction is equal to the elastic deformation of the damper A in Y direction, i.e., the damper is forced leftward and rightward in X-direction at the ratio of 1:1 and also forced upward and downward in Y-direction at the ratio of 1:1. Therefore, the stretching force applied to the damper A by the voice C in X-direction is equal to that in Y-direction. However, the damper A receives a different stretching force at 45° (direction A or direction B). As stated, the damper A is a plain weave fabric of elastic warp wires A1 and weft wires A2. If the stretching force applied to the elastic warp wires A1 and the weft wires A2 in X-direction and Y-direction is 1:1, the stretching force in direction A and direction B (about 45°) will be √2≈1.414, i.e., the stretching force applied to the damper A in directions X and Y and in directions A and B will be 1:1.414, resulting in an unbalanced deformation of the damper A (see FIGS. 6A and 6B). Unbalanced deformation of the damper A may cause the damper A to break, or result in an eccentric motion of the voice coil C (see FIGS. 7 and 8). The voice coil C may strike the driver's magnetic system D directly upon an eccentric motion, resulting in an abnormal vibration or damage, and lowering the sound quality of the speaker or shortening its service life.
Therefore, it is desirable to provide a damper for speaker that eliminates the aforesaid problems.